The web of absorbent substrate may be a web of tissue paper that is obtained by a Conventional Wet Press or Through Air Drying manufacturing method or other manufacturing method. A tissue paper relates to an absorbent paper based on cellulose fibers which is also called tissue paper base sheet in this field of technology. A typical absorbent paper has a low basis weight, in the range from 10 to 60 g/m2, or from 30 to 50 g/m2.
The web of absorbent substrate may also be a web of nonwoven fabric that is obtained by an air-laid manufacturing method or spun-laid manufacturing method or other manufacturing method. A nonwoven fabric including cellulosic fibers relates to an absorbent paper which is also called nonwoven or web made of fibers like air-laid web in this field of technology. A typical absorbent paper has a basis weight, in the range from 20 to 300 g/m2, or from 40 to 60 g/m2.
Rolls of absorbent sheet products for consumers are thick and soft products. Such products show a low resistance to compression (perpendicularly to the axis of the roll/core). This is particularly the case for coreless rolls.
The document GB1554619 describes the manufacturing of a coreless roll. The method includes spraying a water based liquid on a number of turns just before the web material is wound. This enables producing a stable and rigid core with the first turn of web material that is more resistant to collapsing.
However, in the frame of industrial manufacturing, the web material is run at a speed of around 10 m/s (reference in the tissue paper industry is around 600 m/min). Logs of web material are produced and then cut into individual rolls. Further, a consumer toilet paper log/roll has a web length of around 12 m. Furthermore, applying a water based liquid onto such a web material negatively affects the intrinsic quality of the product. This means that only a few numbers of turns should be concerned by the spraying. As a consequence, for treating a few numbers of turns, the water based liquid must be sprayed during less than 1/10th of second. This is technically complex and costly to implement in the frame of industrial manufacturing.
The document U.S. Pat. No. 5,344,091 describes an apparatus and method for winding stiffened coreless roll which include a spiral wound roll formed from this product paper, conventionally paper having a printed pattern or design on one side (i.e. wrapping paper of the type used to wrap birthday and holiday gifts and other package), and a spiral stiffener sheet extending completely around the roll to stiffen the roll. The apparatus receives continuous webs of product paper and stiffening paper, severs the stiffening paper into short lengths for winding into the roll of product paper and automatically feeds the stiffening sheet onto a length of product paper which is wound into a roll. The two webs are fed to either side of a continuous rotating cutter roll. Anvil assemblies are moved into engagement with a knife carried on the cutter roll for selectively severing the webs as required.
However, at the end of the roll, namely when the user attains the last sheet portion of the roll, the last portion with the stiffener paper, or at least the stiffener paper taken separately cannot be used and must be discarded.
Thus, there is a need to improve coreless rolls. In particular, it should be desirable to be able to use coreless rolls of absorbent sheet products that are resistant to collapsing until the last sheet.